Swinging power-operated circular saw



7 Sep'tLBO, 1952 J PATON 2,612,191

Filed NOV. 21. 1949 2 SHEETS-SHEET l SWINGING POWER-OPERATED CIRCULAR SAW Jwavrop thu M. PAM

Airs Esp 1952 J. M. PATON 2,612,191

sw mcmc POWER-OPERATED CIRCULAR SAW Filed Nov. 21, 1949 2 SHEETS-SHEET 2 JIvvEmI? :TAMES IV. PATON Bymwd Arrr.

Patented Sept. 30, 1952 SWINGING rowna-oanaa'rnn CIRCULAR SA 7 J ames M. Paton, Fort William, Ontario, Canada I 1 Application November21, 1949, Serial No. 128,606

; v In Canada. September 2, 1949 1 The invention relates to a swinging power onerated circular saw and is concerned withmeans for holding an article to be sawed as well'as with means for protecting the operator from accidental contact with the saw blade during the sawing operation. I

Prior to the invention, a power operated circu lar saw in which the saw blade was mounted on a swing arm had the disadvantage that when the swing arm was lowered to bring the 'saw blade into contact with an article to be sawed, such as a log of wood, the motion of the saw caused the log to be kicked sideways. The sideways movement of the log often resulted in an uneven cut as well as a severe stress on the drive mechanism for the saw, and, in some cases, the saw blade would become jammed. Another disadvantage was that when the saw was in either its upper position or its lower working position, the lower half of the saw blade was exposed so that an operator could accidentally come into contact with it. To overcome this latter disadvantage,

it has been proposed that a saw guard be pro,-

vided which would completely enclose the saw blade when the saw blade was in its upper position. This guard was provided with a trackwayso that when the swing arm was lowered the lower edge of the guard would contact the upper.

edge of the log causing the guard to be raised vertically as the saw cut into the log. However, this form of a guard had the disadvantage that the part of the saw in engagement with the log was exposed to the operator.v

According to the invention there is provided a power operated circular saw mounted on a swin arm which overcomes both. the disadvantage of movement of the log during sawing and the disadvantage of having part of, the saw blade exposed to the operator. According to the invention an article engaging swing arm is pivotally fixed to the saw swing arm at a point between the point of pivoting of the saw swing arm and the axis of rotation of the saw blade. The article engaging swing arm extends inthe same general direction as the saw swing arm and has a set of teeth which engage the upper part of the article to be sawed when the saw swing arm is lowered. Means is provided to rotate the circular saw blade in a direction such that the edge of the blade nearest the article to be sawed moves toward the point of pivoting of the saw swing arm. In a preferred form of the invention the article engaging swing arm has a saw guard fixed to it so that the guard extends downwardly in a vertical direction to protect the part of the saw blade which extends beneath the saw swing arm.

Clainis. (01. 143-46) In acii'cular saw machine according tothe invention, the article to be sawed is firmly held against the bed of the machine during thesawing operation by the teeth ofthe article engaging swing arm. The bed of the machine, according to this specification and the attached claims, is meant to include the means of supportfor the article to be sawed, for example, a conveyor. The firm engagement of the teeth with the article to besawed is due to' the point of pivoting of the second swing arm being between the point'of pivoting of the first swing'arm and the axis of rotation of the circular saw blade. As the saw swing arm is lowered, it causes the'article enr gaging swing arm 'to move longitudinally of itself away from the point 'of pivoting of the saw swing arm and across the article to be sawed. This movement of the article engaging arm, which is in a direction opposite to that of movement of the edge of the circular saw blade in contact with the article, causes'the setof teeth on the article engaging swing arm to be firmly jammed into the article to be sawed holding it firmly against the force of the rotating'circular saw blade. In the preferred form of the invention referred to above, the downwardly extending guard moves with the articleengaging swing arm and protects the operator from contact with the part of the circular saw blade which engages the article to be sawed. j r

The invention will be further'describe'd by reference to the attached drawings which illustrate an embodiment of it, and in which: Figure 1 is a side elevation of the D'QWG T operated circular saw according to the invention;

FigureZ is a planview of the sawshown in Figurel,a nd A Figure 3 is a cross section taken on the line 3-3 of Figure 1.' V

As shown in the drawings, a-'swing' arm I0 is mounted in a cradle H' which is pivotally fixed on a bearing l2 to a bed 13 of the circularfsaw machine. The circular saw blade i l'is rotatably mounted by abearing 15 at one end of the. swing arm I0. At the other end of the saw swing arm 10 is a counterbalancing weight I6 which may be adjusted to a suitable position along the swing arm [0 and the swing arm I0 may be moved longitudinally in the cradle II for adjustment purposes. As shown in Figures 2 and 3, the circular saw blade I4 is driven by a belt I! running over a pulley I8 on a shaft 19 to which the circular saw blade I4 is fixed. The other end of the belt I! is driven by a pulley 20 fixed to a shaft 2! which extends through a bearing 22 to a drive pulley 23 and an idler pulley 24.

with the part of the saw blade l4 while it is in engagement with the log 34.

What I claim as my invention is: l l. A power operated circular saw comprising, a saw swlng arm, means for pivotallysupporting the saw swing arm, a circular saw blade operatively mounted on the saw swing'arm, an article engaging swing arm pivotally fixed to the saw branches 21a and 21b to the saw swing arm I8- at a bearing 28 in an extension 29 of the cradle H. The article engaging swing arm 21 extends to the outer edge of the guard 25. and has a curved section 30 above the bearing 15. A oracleet 3| is attached to the curved section 3510f the A swing arm 2'! and holds a rubber bumper 32 which rests against the outer surface of the bearing It when the circular saw blade M is in the upper position shown in solid line in Figure 1. At the outer end of the article engaging swingarm 2?. is an intermediateguard 32 and a lower guard 32a which extend in a vertical direction downwardly in front of the cutting edge oi the circular saw blade M. Along the lower edge of the article engaging swing arm 21 is a set of teeth 33 which are adapted'to engage the upper part of an article to be sawed such as a log 34 as shown in the figswing arm at a point at a substantial distance from the pointof pivoting of the saw swing arm but between said point of pivoting'and the axis of rotation of the circular saw blade, a set of teeth 7 located on the article engaging swing arm so that ures. The log 34 is brought into position beneath the circular saw blade 14 by passing it along the rollers 35 of a conveyor 36 which forms part of the bed l3 of the machine.

,In operation the circular saw blade i is driven by power applied to the pulley 23 and transmitted to the belt 11 which drives the shaft 19. The direction o'f-irotation of the circular saw blade M is such that the edge of the blade M next the log 3 moves in a direction toward the bearing l2 of the saw swing arm It as shown by the arrow in Fig. 1. When the log 3A is brought intoposition beneath the circular saw blade M the saw swing arm i6 is lowered bringing the lower part or the cutting edge of the sawblade l4 into contact with the upper edge of the log 34. At the same time, the

edge of the blade M contacts th-eupper edge of the log 34, or preferably justbefore the blade contacts the log 34, the set of teeth 38bears downwardly. on" the upper part of the log 34 and is pushed in a horizontal direction across the top of the log 3i due to the downward motion of the arm [0 displacing the pivot pointer the article engaging arm 2'! in 'a direction toward the log 3%.

.The combined downward and horizontal movement of the teeth 33 causes them to bite into the surface or the log 34 and at the same time apply a force to the log 34 which opposes the force acting on the log 34 due to the rotating saw blade 14. As the saw blade 14 bites into the log 34 the teeth 33 on the article engaging swing arm 21 maintain their firm hold on the log 34 due to the downward motion of the saw swing arm l0 and, at the same time the intermediate guard 32 and the lower guard 32a, move downwardly providing complete protection for the operator from possible contact blade not covered by the upper guard.

- the teeth engage'the part of an article first to be i cut by the saw during operation of the saw and tend to urge said article away from the point of pivoting the saw swing arm, and means for ro-- tating the circular saw blade in a direction such that the edge of-the circular sawbladeen'gaging:

e the article to besawed moves-toward the point ofis pivotally fixed to the saw swing arm at a point,

closer to the point of pivoting of the saw swing arm than to the axis ofrot'ation-of the circular saw blade. r

3. A power operated circular saw-according to claim 1 in which the'article engaging swing arm is supported by the saw swing arm when the cir cular saw blade isou-t'of ea agemeetwlth the article to be sawed. I

4. A power operated circular saw aceording to claim 1 which comprises an iipper gua-rd fixed to the saw swing arm and covering thee'd'ge of the circular saw blade extending above the saw swing arm, and a guard telescopic with the upper guard and so 'fixed'to the articleehgaging swing arm as toextend in a vertical direction in front of at least part of the cutting edge of the circular saw 5; A power operated circular sawaccordin to claim 4 in which the articleengaging swing arm Number Namei 1 Date 410,777 Abbott .Q .l Sept. 10, 1389 l,i8l,569 I Tannewitz Jan. 22 1924 2,310,152 .Rorining; Feb. 2, 1943 2,420,836 3 Nelson May 20, 1947 FOREIGN enfrirurs Number I Country v I 67,680 I v Date 

